String bucketName = "examplebucket-1250000000";
String key = "qrcode.png";
GetObjectRequest getObj = new GetObjectRequest(bucketName, key);
// 宽高缩放为原图的50%
String rule = "imageMogr2/thumbnail/!50p";
getObj.putCustomQueryParameter(rule, null);
cosClient.getObject(getObj, new File("qrcode-50p.png"));

String bucketName = "examplebucket-1250000000";
String key = "qrcode.png";
GetObjectRequest getObj = new GetObjectRequest(bucketName, key);
// 裁剪内切圆的半径，取值范围为大于0且小于原图最小边一半的整数。内切圆的圆心为图片的中心
String rule = "imageMogr2/iradius/150";
getObj.putCustomQueryParameter(rule, null);
cosClient.getObject(getObj, new File("qrcode-cropping.png"));

String bucketName = "examplebucket-1250000000";
String key = "qrcode.png";
GetObjectRequest getObj = new GetObjectRequest(bucketName, key);
// 顺时针旋转90度
String rule = "imageMogr2/rotate/90";
getObj.putCustomQueryParameter(rule, null);
cosClient.getObject(getObj, new File("qrcode-rotate.png"));